Fabrication of novel tetrahedral Ag3PO4/g-C3N4/BiVO4 ternary composite for efficient detoxification of sulfamethoxazole

Abstract

Wide spread of antibiotic resistant microorganisms and genes urge the evolution of effective methods to remove antibiotic pollution from the environment. Ag3PO4 is one of the best visible light photocatalyst but has drawbacks due to low stability. Combining Ag3PO4 with BiVO4 and g-C3N4 is expected to overcome these drawbacks and improve the efficiency. The present study deals with preparation of tetrahedral Ag3PO4/g-C3N4/BiVO4 ternary composite with superior photocatalytic activity and stability for efficient detoxification of sulfamethoxazole (SMX). Pure BiVO4 (51.3 %), g-C3N4 (40.2 %), Ag3PO4 (60.1 %) and other composites showed lower efficiency than Ag3PO4/g-C3N4/BiVO4 (93.6 %) in photodegradation of SMX (20 mg/L) after 60 min. Tetrahedral Ag3PO4 showed superior light adsorption capacity and photocatalytic activity when combined with g-C3N4/BiVO4 and also showed reduced charge recombination which were supported by UV-DRS and PL analysis. The synergistic effects of both g-C3N4 and Ag3PO4/BiVO4 in the structure could facilitate the enhanced photostability and recyclability to Ag3PO4. Furthermore, the intermediate compounds generated during degradation of SMX were analyzed by LC-MS analysis and the plausible pathway was proposed. Moreover, the biotoxicity of the intermediate compounds was investigated by Escherichia coli (E. coli) colony forming unit assay and the results revealed that after 60 min a substantial decrease in biotoxicity was observed.